The present invention relates to digital processing. The present invention finds particular application in tomographic image reconstruction and will be described with particular reference thereto. However, it is to be appreciated that the invention is also applicable to other types of image and data processing.
In the field of computerized tomographic scanners, the accurate reconstruction of images is of utmost importance. One of the major drawbacks in accurate image reconstruction has been the amount of time necessary to complete the image reconstructions for each scan of a multi-scan procedure. The longer the time necessary to complete the image and initiate the next scan of the procedure, the more likely procedure degrading occurrences, such as patient movement, become.
Improving the speed of data acquisition or once data has been acquired, increasing the speed at which it is manipulated increases the speed of reconstruction of the scanned image. Central to the reconstruction of an image is a convolution process which prepares the data for backprojection into image. The speed of the convolution process is a constraint on the speed of the total system. Faster convolution achieves faster image reconstruction allowing for more accurate scans and less scans which must be re-performed.
As part of this convolution processing, data is stored at memory locations until it is needed for necessary mathematical computations. In the past, the conventional random access memory structure was used. It normally had a single port structure such that only one memory location could be accessed during a single clock cycle. While others have proposed using a dual port random access memory, only two memory locations could be processed per clock cycle. Both access speeds were so slow that mathematical operators in the system functioned below their theoretical top speeds.